I have a Simaudio Moon 110LP phone preamp amplifying a Dynavector 20X2L cartridge on a VPI Classic. It feeds in to an Outlaw Audio RR2160 amp which drives Magnepan LRS speakers.
I recently moved and two months in I realized my speaker placement wasn’t quite right, so today I reorganized my listening room. This involved unplugging some power cables but I kept most of the interconnects in place. I did have to disconnect the phone stage from the amplifier.
After getting things back into place, I listened to some music using coaxial input before reconnecting the interconnects of the phono stage. When I tried to, I actually got some electric current that burned my hand slightly. This came from the back of the amplifier. I made sure everything was unplugged and tried again - this time a spark and smoke from the interconnect making contact to the back of the amplifier.
I’m so confused why this would happen, but eventually I did get everything connected. Now the output from the phono stage is just a bump every 1 second. It doesn’t amplify the signal from the TT.
My amplifier has a built in phono stage and using this I was able to verify that the turntable is still producing a signal. The built in phono stage sounds terrible, however, as thin and flat as paper. It is music, however.
When I connect the phono stage to the power, the blue light on the front illuminates for a moment and then goes dark.
Incredibly, when I was unplugging the phono preamp, I actually got some current from simply touching the exterior of the box. Something is seriously wrong and dangerous with my setup, and this box was grounded to the turntable with a ground cable, which was connected to the outlet with a three prong cable with ground.
Has anyone experienced anything like this before? I will email Simaudio and see if they’ll repair it. I’m also taking recommendations for replacements. I liked the 110LP and maybe will just replace with the 110LPV2.
i unplug the preamp from power. [ME (Dead NO power)]
I unplug all interconnects from preamp.
I leave the grounding wire connected, which grounds the preamp to the record player tone arm.
I put one lead of the multimeter in the EGC coming from the outlet where the preamp, amp, and CDP are connected,
and the other lead on the RCA output of the preamp
and I read 121Vac on LoZ.
I now unplug the (grounded) power cord from the turntable
and do the same test (still with the ground cable attached to the preamp and the tone arm) and see 0Vac.
/ / / / / / /
My response:
Sounds to me the difference of potential, voltage, of 121Vac is coming from the TT 120V power section that feeds power for the motor.
121Vac fault circuit path through the mm volt meter.
121Vac Hot conductor from wall outlet to >>> TT motor section to >>> tone arm ground to >>> ground wire to >>> phono preamp ground lug, metal enclosure of preamp, signal ground (outer shell) RCA jack to >>> test probe lead of muli-meter >> through volt meter >> out test lead probe wire to >>> EGC of wall outlet.
The two points for the voltage,
(1) the Hot conductor at the wall outlet that feeds the TT
* (There has to be problem in the 120V section of the TT. Will need to check that out)
(2) The EGC at the wall outlet that feeds the CDP and unplugged phono preamp
Your job now is to verify there is continuity from the 120Vac Hot prong on the TT IEC inlet connector and the tone arm ground. That just don’t seem possible...
You get to try out the continuity setting on the mm.
For this there can’t be any LIVE voltage at the points you will measure for continuity.
Leave TT unplugged.
Test:
Power Switch on TT must be Switched ON...
First set mm to V
Measure for voltage from the tone arm ground lug to one of two line prongs. I don’t know which one is the actual Hot prong so you will measure from both.
You should measure zero volts from each one (on the IEC) to the tone arm ground lug.
No voltage... Correct?
Next move the switch on the mm clockwise one setting. That should be the continuity setting.
Touch both metal probes to one another.The meter should make an audible sound. You probably will see something displayed on screen as well. (It will in the mm instruction manual.)
Next, touch one mm probe to the arm ground lug and the other probe to each of the outer prongs on the IEC inlet connector.
May may not hear the audible sound, look at the mm display. It may show a low resistance measurement.
i unplug the preamp from power. I unplug all interconnects from preamp. I leave the grounding wire connected, which grounds the preamp to the record player tone arm. I put one lead of the multimeter in the ECG coming from the outlet where the preamp, amp, and CDP are connected, and the other lead on the RCA output of the preamp and I read 121Vac on LoZ.
I now unplug the (grounded) power cord from the turntable and do the same test (still with the ground cable attached to the preamp and the tone arm) and see 0Vac.
note: The turntable is connected to a different power outlet than the preamp and the amplifier. the turntable is off the whole time.
the building I’m in, yes it’s old (I think maybe 100 years) and I rent. I will need to test the outlets where the TT is plugged in tomorrow.
I just plugged everything into all the outlets as it was last weekend (minus the interconnects between phono and amp) and re-did the test where one lead is on preamp output, one on amp analog 1 input rca plug.
121Vac on V
68.9Vac on LoZ
0Vdc on V
isnt that it? 69Vac on LoZ is a major issue, right?
I then unplugged the grounded 3 prong power cord from the cd player and the voltage registers ~0Vac on LoZ between the RCA output on the preamp and the rca input on the amp.
both amp and preamp were on at that time.
i then turned the amp off and turned off its power switch but left it connected to the wall and the same readings were registered.
if this is the problem I think it is, I need your help to understand what the core source of the problem is and what piece of equipment is misbehaving.
On the good power cords, the ground connection (round pin of plug) is longer than the flat pins....that means the unit is grounded until the last little bit of plug is removed from the wall.
his wouldn’t be a big deal if the three other RCA inputs still worked. Last weekend I connected the preamp to analog input 4 on the amp and it made the same soft bump sound. I just remembered the blue sound node also has an integrated DAC and RCA out. So if I don’t mind risking frying it I could try connecting it. Ideally I should find something cheaper, maybe my TV (which is old and I don’t use). I’ll check if it has RCA out when I get home.
Before you do anything run a quick test on the RR2160 amp. Need everything associated with the audio system plugged into the120V wall outlets as they were the day of the spark event. Need all ICs connected, except the ICs of the phono preamp, to the RR2160 amp.
Test:
I want you to measure from an analog RCA jack input (that you have not connected the phono preamp to) outer signal ground shell to the wall outlet EGC.
Problem may be you can't unplug any audio equipment from a wall outlet to use the power cord for a test lead extension. You could use a 3 wire grounding type drop cord and use the EGC from it. Just make sure the wall outlet you use has an EGC. You know how to test for that.
If it's easier for you can plug an IC into the RCA jack on the RR2160 amp and touch the mm test lead probe to outer shell of it.
Set the mm to V ac .
For the heck of it after measuring from the input signal ground of that jack to EGC ground, repeat the test on the the analog input jack signal ground you oroginally had the phono preamp ICs plugged into. The day of the electrical shock, spark event.
Note... Inside heavy light gray line is me. Outside heavy light gray line is you.
Saturday, check for voltage from the outer shell of the output RCA jack of the phono preamp to the outer shell of the analog input RCA jack on the RR2160 amp.
Should of done that to begin with...
Both units powered on.
5.5Vac on V
0.02Vac on LoZ
My response:
Could you check again using the DC setting.
LoZ is not needed for either AC or DC in this case.
Question:
I didn't think about until just now. Was all associated audio equipment still plugged into the same 120Vac outlets? Especially the CDP? It doesn't need to be turned on, just plugged into the wall outlet. At present the CDP is the only piece of equipment the uses an EGC that is connected to the RR2160 amp with ICs.
Need to have everything connected the same way as the day you received an electrical shock and the spark event.
.
.
jea48
When you get a chance check the wall outlets the equipment plugs into for proper Hot / Neutral polarity and for equipment ground. At least you will be able to check them off your list.
You
I sent a lot of messages last night so perhaps you missed:
You
I tested the outlets where things were plugged in. The hot/neutral is reversed. So the hot is the longer left slot, the neutral is the shorter slot on the right. The ground appears to be functioning.
My response:
Larger of the two slots is the neutral side of the receptacle. You measured 120Vac to EGC ground. (Hot black ungrounded conductor is connected to neutral terminal)
Smaller slot is the Hot side of the receptacle. You measured zero nominal volts to EGC ground. The white color "Grounded Conductor", "White neutral conductor", is connected to the Hot terminal of the receptacle.
Yes, the branch circuit wiring, Hot and neutral conductors are reversed (wire wrong) on the duplex outlet.
.
.
You
Explicitly, this means when I’m on V or LoZ and I go into hot/neutral I get 120Vac. When I go neutral/ground I get close to zero, and when I go neutral/hot I get ~120Vac. However, hot/neutral is reversed.
????
You're starting to sound like me late last night...
However, hot/neutral is reversed.
On that I agree.
i don’t think it matters but when I plug one lead of MM into ECG and the other isn’t connected to anything I get 5V on V but it disappears of course on LoZ.
Well.... Though the Audio system equipment probably has been in use, operating Ok plugged into wall outlets with the Hot and neutral branch circuit conductors reversed, wired wrong, For now I think we can over look it. But with that said it needs to be corrected.
Question... Are you renting or do you own the residence? Is the electrical panel located in the dwelling? Are the wall outlets on opposite sides of the room on the same breaker in the electrical panel. Roughly how old would you say the building, electrical wiring might be?
I realize the electrical wiring issue is off tract at the present. At some point, after we figure out the problem with your audio system we will come back to it.
I haven’t mentioned it yet. You may have damaged the analog L & R input circuitry in the RR2160 amp. The pair of RCA jacks you plugged the ICs into from the phono preamp.
This wouldn’t be a big deal if the three other RCA inputs still worked. Last weekend I connected the preamp to analog input 4 on the amp and it made the same soft bump sound. I just remembered the blue sound node also has an integrated DAC and RCA out. So if I don’t mind risking frying it I could try connecting it. Ideally I should find something cheaper, maybe my TV (which is old and I don’t use). I’ll check if it has RCA out when I get home.
I’m obviously leery of connecting them again but if there’s some way to do so safely I might be willing to try. Thanks for all your help.
NO, I wouldn't if it was my equipment.
I haven't mentioned it yet. You may have damaged the analog L & R input circuitry in the RR2160 amp. The pair of RCA jacks you plugged the ICs into from the phono preamp.
I haven't mentioned trying to connect a different source to any analog inputs on the amp as yet. You don't know yet what what is causing the problem.
I will go back to you previous post I was reading and respond to it.
Saturday, check for voltage from the outer shell of the output RCA jack of the phono preamp to the outer shell of the analog input RCA jack on the RR2160 amp.
Should of done that to begin with...
Both units powered on.
5.5Vac on V
0.02Vac on LoZ
When you get a chance check the wall outlets the equipment plugs into for proper Hot / Neutral polarity and for equipment ground. At least you will be able to check them off your list.
I sent a lot of messages last night so perhaps you missed:
I tested the outlets where things were plugged in. The hot/neutral is reversed. So the hot is the longer left slot, the neutral is the shorter slot on the right. The ground appears to be functioning.
Explicitly, this means when I’m on V or LoZ and I go into hot/neutral I get 120Vac. When I go neutral/ground I get close to zero, and when I go neutral/hot I get ~120Vac. However, hot/neutral is reversed.
i don’t think it matters but when I plug one lead of MM into ECG and the other isn’t connected to anything I get 5V on V but it disappears of course on LoZ.
Question... Is the SMPS 120Vac plug in blades the same width or is one wider than the other? Therein polarized. If both blades are the same reverse the SMPS 180 degrees in the receptacle and perform the test for high voltage again.
the blades are the same width. For the following test I plugged the SMPS into the wall in the same configuration as it was in when the incident occurred.
I don’t know what I was thinking yesterday... I should of had you do the tests with the phono preamp connected to the SMPS. Therein the connected load. Likely a defective connected load that might be overloading the SMPS. A real world test...
ok I did this test following your 7 instructions and got the following readings:
52.5Vac on V
0.16Vac on LoZ
i know you said LoZ not necessary but I did it and again the voltage disappeared.
0 on DC on V and LoZ (I looked into ghost voltage and it seems like a purely AC phenomenon).
i was watching the blue light on the 110lp as i was doing this test and it was blinking continually. I made a video: https://youtu.be/Dcaxu_ZM6VQ?si=sj70-NxTUOHN3noQ. The blinking did NOT fade away but kept going like this faintly.
I remember last weekend when I had the preamp connected to the amp’s analog 1 input and I listened, I heard a ‘bump’ paced exactly the same as this blue light’s blink. This was as a record was playing and the preamp was connected to the TT. I heard no music just this gentle regular bump.
I’m starting to think neither component (amp or preamp) is behaving evilly on its own (although the preamp seems clearly broken), but only together there is a toxic combination. Note, I used these components together fruitfully for the last 3 or 4 years. It was only when I moved them last weekend that disaster struck. It’s also conceivable to me that the preamp was dangerous but now some circuit is shot and it’s not dangerous anymore. I’d also like to test connecting something else to the RCA input on the amp but I’m not sure I have anything I can test. Maybe my TV. As mentioned I did connect the TT directly to the phono stage of the amp last weekend and it did function normally, just was unlistenable (because of how bad the integrated phono stage is).
I’m obviously leery of connecting them again but if there’s some way to do so safely I might be willing to try. Thanks for all your help.
and yes, I’ve been listening to music off the amp using the node (am doing so right now) and it sounds great. (Hariprasad Chaurasia today.)
one more remark: when I was trying to connect the IC from the preamp out to the amp analog 1 input last weekend, the whole general area of the rear of the amp felt dangerous. It wasn’t just the rca plug. It might have also included the speaker wire which is securely seated in the amp. On this point, you saw the crater on the IC exterior in my video but I’ve been unable to see any corresponding damage to the amp. I just looked closely. It almost seemed like the spark jumped from the air and landed on the IC. I don’t know if this is possible.
@mark200mph thank you. Fortunately I can still listen to music over digital and that is what’s keeping me sane.
I could be wrong, ( the amp hasn’t been checked out yet) but I think the phono preamp is the problem.
I base that on this resent post from the OP.
But since all this I’ve listened to about 3 hours of music using the amp with no issues whatsoever (phono disconnected of course).
.
He also posted the same thing earlier in the thread.
@jea48 RR2160 amp has built in DAC and has two coax inputs. One to CD player one to bluesound node. Since this episode I’ve been listening to music off the node without problems.
In looking at the forums alot of the outlaw amps had a ground loop hum and people were going from 3 to 2 prong bypassing the ground.as stated above this is frowned on.hope you get this fixed.there are alot of smart people on here some are electric engineers. Good luck and make sure you have an observer that can throw the breaker off or some surge protector that can trip.when we built our hospital the young apprentice electrician got fried on the roof .we could not save him be careful.
At some point i was going to buy an outlaw amp but I read a thread that a few people said it caught on fire I would not plug that back in .I don't rember it being an audiogon thread.this could be destructive to all your equipment.be careful.
I don’t remember reading a post where you responded to this.
If you did not read, measure, high voltage, or any voltage... Question... Is the SMPS 120Vac plug in blades the same width or is one wider than the other? Therein polarized. If both blades are the same reverse the SMPS 180 degrees in the receptacle and perform the test for high voltage again.
That is from the long winding thread I posted yesterday.
.
One other thing I didn’t think about yesterday. The tests for the SMPS I had you do for checking for AC mains high voltage on the output side of SMPS were unloaded.
I don’t know what I was thinking yesterday... I should of had you do the tests with the phono preamp connected to the SMPS. Therein the connected load. Likely a defective connected load that might be overloading the SMPS. A real world test...
Probably also should have had you use the wall outlet that the SMPS is normally plugged into. IF, one of the blades is not polarized, therein it could be plugged in either way, it would be plugged in the direction that caused the electrical spark fault event.
.
IF you want to try the test again.
Test procedure is a little different than yesterday.
You will still use the OEM 3 wire power cord to connect one of the mm test lead probes to the wall EGC. ( an extension of the probe lead)
1) Set up for the test.
Before the SMPS output power cord connector is plugged into the phono preamp.
Connect an IC (interconnect cable) into one of the RCA output jacks on the preamp. Extend the other end of the IC so it will be easy for you to touch the other test lead probe of the mm to the outer ground shell of the IC RCA plug.
2) insert the mm black test lead probe into the female EGC ground contact of the plugged in OEM power cord.
3) Set mm to "V". (mm will default to V AC.)
4) Plug SMPS output power cord connector into phono preamp. (Blue light starts doing its’ thing. Preamp has DC power. SMPS has a load on its’ output)
5) Touch mm test lead probe to the outer ground shell of the IC RCA plug.
What voltage is measured, displayed, on the mm? No need to check for LoZ voltage. The connected load of the preamp is more than enough load. LoZ would only add a small additional load.
6) Check again for a voltage reading after the blue light on the front of the preamp is no longer lit for any difference of voltage measured.
7) Just to cover all the bases... Repeat the test measuring for DC voltage. You probably should let the phono preamp do a reset by disconnecting the SMPS power cord plug from the preamp. Just trying to cover all the bases.
Yes I verified your question about subwoofer in earlier comment today. The subwoofer pins are only two even though the power cord has three prongs. So I assume it’s ungrounded. But note the CDP is grounded and the amp is sitting on top of it and connected via coaxial cable.
Yes the sup amp is ungrounded. AC power wiring in the sub amplifier is double insulated.
So where was the spark fault current path? What is the source.
No doubt there is a difference of potential, voltage, between the output of the phono preamp and the RR2160 amp signal ground, (outer shell) of the analog input jacks.
Saturday, check for voltage from the outer shell of the output RCA jack of the phono preamp to the outer shell of the analog input RCA jack on the RR2160 amp.
Should of done that to begin with...
Both units powered on.
.
I think we are back to square one.
When you get a chance check the wall outlets the equipment plugs into for proper Hot / Neutral polarity and for equipment ground. At least you will be able to check them off your list.
I think I messed up on the DC measurements, i think they were AC. so let me try again:
SMPS (one lead in ground of OEM ITC, the other on the sleeve contact of the SMPS):
0.6 mV DC on V
0.0 mV DC on LoZ
SMPS (red lead center, black on sleeve):
18.15 V DC on V
18 V DC on LoZ
SMPS (one lead in ground of the OEM IEC connector of the power cord , the other on the sleeve contact of the SMPS):
0.6 mV DC on V
0.0 mV DC on LoZ
Multi-meter should have been set to AC voltage not DC. I am looking for AC mains voltage on the SMPS output power cord connector. The measurements would be good if only AC measurements.
.
SMPS (red lead center, black on sleeve):
18.15 V DC on V
18 V DC on LoZ
This is correct. Voltage looks good.
That doesn’t mean there is not a problem with the preamp. I believe there is. The Blue power light maybe saying there is.
Again, I would NOT connect the input or output of the preamp to any equipment.
I tested the outlets where things were plugged in. The hot/neutral is reversed. So the hot is the longer left slot, the neutral is the shorter slot on the right. The ground appears to be functioning.
Does the 120Vac IEC inlet connector on the back of the sub have three prongs? Therein an equipment ground prong? My bet is yes. Correct?
Yes I verified your question about subwoofer in earlier comment today. The subwoofer pins are only two even though the power cord has three prongs. So I assume it’s ungrounded. But note the CDP is grounded and the amp is sitting on top of it and connected via coaxial cable.
Was the SMPS unplugged from the 120Vac wall outlet or the power cable from the SMPS disconnected from the phono preamp? Preamp was dead?
I believe it was plugged into but I’m not confident on this. But moreover I was trying to connect the interconnects; at some point they were connected, then they were disconnected. So when I felt current on the enclosure of the amp I do not know what was connected to what.
Yes agree. But, my understanding is the SMPS was feeding power to the phono preamp at the time. Correct?
SMPS (one lead in ground of OEM ITC, the other on the sleeve contact of the SMPS):
48V on V
0.13V on LoZ
thoughts?
48V AC on V Might not be real power.
0.13V on LoZ real power .... ???
Thinking on this one.
.
SMPS (red lead center, black on sleeve):
18.5V on B
0L and it beeps on LoZ
18.5Vdc on V correct?
0L and it beeps on LoZ. I may have read the instruction manual wrong. LoZ may only be for AC voltage.
.
I can test the outlets where things are plugged in too.
Yes, check them.
.
and to elaborate: yes I felt current on the enclosure of the preamp. I also felt current, I believe, on the enclosure of the amp at some point. And when I connected the tone arm ground cable to the amp ground (the amp has a built in phono stage), there was also a spark.
Was the SMPS unplugged from the 120Vac wall outlet or the power cable from the SMPS disconnected from the phono preamp? Preamp was dead?
.
I believe current was flowing through the interconnects between phono preamp and amp,
Yes agree. But, my understanding is the SMPS was feeding power to the phono preamp at the time. Correct?
.
But since all this I’ve listened to about 3 hours of music using the amp with no issues whatsoever (phono disconnected of course).
i then unplugged the phono, connected it to TT via RCA Input on phono, plugged in again. Measured 49V with red lead on the shield of the interconnect plugged into the R input of the phono, which dropped to 0.14V on LoZ
I would NOT connect the input or output jacks of phono preamp to anything .
I plugged in the preamp to the wall using its SMPS.the blue light went on, off, on, off four times getting fainter then went off.
I plugged the black lead into the ground of the OEM IEC power cable. I put the MM on V. Red lead on any one of the four RCA inputs/outputs of phono stage. Same reading as in the SMPS: 48V, but when I switch to LoZ, drops to 0.128V.
i then unplugged the phono, connected it to TT via RCA Input on phono, plugged in again. Measured 49V with red lead on the shield of the interconnect plugged into the R input of the phono, which dropped to 0.14V on LoZ
SMPS (one lead in ground of OEM ITC, the other on the sleeve contact of the SMPS):
48V on V
0.13V on LoZ
thoughts?
SMPS (red lead center, black on sleeve):
18.5V on B
0L and it beeps on LoZ
Note: this wasn’t using the outlet where everything is currently plugged in. I used a spare outlet. I can test the outlets where things are plugged in too.
and to elaborate: yes I felt current on the enclosure of the preamp. I also felt current, I believe, on the enclosure of the amp at some point. And when I connected the tone arm ground cable to the amp ground (the amp has a built in phono stage), there was also a spark. I believe current was flowing through the interconnects between phono preamp and amp, but i don’t know the source. But since all this I’ve listened to about 3 hours of music using the amp with no issues whatsoever (phono disconnected of course).
Hopefully you can understand my long above post. Looks like I should have proof read it a couple of times after posting it. I spotted a few double words here and there.
I corrected a couple of poorly worded sentences in my post above. Read through the Long post... I will check your thread occasionally tonight for any posted questions you may have.
I watched your video a couple of times again today. I can’t explain why the SMPS could pass an AC mains voltage to the phono preamp, You wouldn’t think it could... But, you said in the video you received an electrical shock touching the metal enclosure of the preamp. The power supply DC B-, and circuit signal ground, is connected to the preamp metal enclosure, directly or indirectly. If not the enclosure would act as an antenna.
I will test now following your instructions and report back. The subwoofer plug into the wall has three prongs but when it plugs into the subwoofer it has only two. So it’s not grounded either. I will be around for the next few hours and will send messages as I proceed through your instructions. Thanks so much.
Assuming the subwoofer uses the EGC, (Equipment Grounding Conductor) from the 120V wall outlet,
and assuming the sub amplifier’s circuit ground is connected to the chassis, (high probability),
and therefore the return signal ground in the RCA interconnect cable is connected to the signal ground of the RR2160 amp,
And therefore the circuit signal ground of the RR2160 amp is, (high probability), connected to the chassis, either directly or indirectly, the RR2160 amp is grounded to the 120Vac wall outlet EGC.
.
Therefore, the first thing I want you to check is the output voltage of the plug-in SMPS Wall Wart) for the phono preamp.
You might want do the test on a kitchen counter top or a table.
mm meter.
Install the two test leads. Black lead in COM jack. Red lead in VΩ jack.
This test will, should, tell if the SMPS power supply has some kind of an internal fault that somehow is passing a high AC mains line voltage to the output of the power supply.
For the test you might want to use a factory OEM three wire grounding type power cord. The center offset ground IEC EGC ground contact will be used to hold the black lead probe tightly in the EGC ground contact. That will free up a hand...
Set the mm to V (volts). V is to the right side of OFF. mm will default to AC volts.
First check the wall receptacle outlet, you will be using, for the correct Hot / neutral AC polarity. At the same time you will be checking checking for an EGC ground.
Insert a test lead probe into each of the two straight slots contacts. You should measure 120Vac nominal.
FYI (If the duplex outlet is a 20A the neutral will have a "T" slot. If a 15A duplex receptacle the neutral contact will be the longer slot of the two parallel slots. Therein the Hot is the shorter of the two.
Next insert a test lead probe in the small slot Hot contact of the receptacle. Insert the other test probe in the ground hole. You may have to move the tip of the probe to one side or the other to make contact to the ground contact. You should measure, read, 120Vac nominal. The same voltage as you measured from Hot to neutral. This shows two things. The hot /neutral wiring AC polarity is correct and an EGC ground is present.
(FYI the reading could be slightly higher due to a loaded VD (Voltage Drop) on the hot and neutral circuit.)
One last test. Measure for voltage from the receptacle neutral contact to the ground contact. (Using a wall duplex receptacle I measured 1.4mV ac.
(Note. On a regular grounding type receptacle the center trim screw that holds on the outlet cover plate is also connected to the EGC ground. You can also use the screw head for the ground connection. Insert probe tip tightly against the straight recessed slot for the screwdriver to make a good electrical contact.)
FYI, use the same method above to check the two wall duplex receptacles that feed your audio system equipment, for the correct hot/neutral polarity and and the EGC is present.
.
Finally, testing the plug-in SMPS.
Plug the OEM power cord into the wall 120Vac receptacle outlet. (Outlet has been checked, OK.)
Set the mm to V (volts). mm will default to AC volts.
OEM IEC power cord. Insert one test lead probe in one of the outside female contacts. Insert the other probe in the other outside female contact. You should read around 120Vac, nominal.
Insert one test lead lead probe in the center offset ground contact. Insert the other test probe in one of the outside female contacts.... From Ground to Hot contact you will measure 120Vac nominal.
Leave the test lead probe inserted in the ground contact of the IEC power cord.
Plug in the SMPS into the same duplex outlet as the OEM power cord.
Be careful, the outer sleeve contact of the SMPS power cord connector may be Hot voltage ground.
Next, depending on how much time has elapsed the MM may have to be shut off. Then turn mm selector switch back to "V" (Volts).
Next touch the other test lead probe to the outer sleeve contact of the SMPS output cord power connector. Does the mm meter display a AC voltage? How high of a voltage?
If you measure a high voltage you need to check it’s a real power voltage and not a false phantom voltage.
Remove test lead probe from the SMPS output cord connector. Turn mm selector switch to LoZ setting. (Last setting on right side of off.) Never change the selector switch with lead probes connected to a possible live voltage.)
Check for the high voltage again on the connector sleeve contact.
Also measure for a voltage to the center female contact of the power connector.
.
If you did not read, measure, high voltage, or any voltage... Question... Is the SMPS 120Vac plug in blades the same width or is one wider than the other? Therein polarized. If both blades are the same reverse the SMPS 180 degrees in the receptacle and preform the test for high voltage again.
.
If still there is no voltage readings, you should then check the output DC voltage of the SMPS to make sure it is working properly.
Remove test lead probe from the ground contact of OEM IEC power cord.
Test;
Set MM selector switch to "V" (volts)
Press the SEL button once to switch to DC volts. mm should display V DC.
Voltage test. 18Vdc female connector. Without touching the metal probes with your fingers... Touch, contact, the RED lead probe to the center female contact, of the power connector and touch the BLACK lead probe to the outer metal sleeve of the connector, both at the same time. You should read + 18Vdc nominal. If you do not read +18Vdc make sure you a making a good contact to the connector.
You can Also use the LoZ setting as well. Rotate the selector switch to LoZ. Press SEL button. mm should display V DC. Red lead probe to center contact. Black lead probe to outer sleeve contact on power connector.
FYI the outer sleeve electrical contact is B- negative of the DC power supply. It also should be circuit ground of the power supply and Phono preamp when connected to the preamp.
If it does not read +18Vdc? or the meter reading is + - + - + - + repeatedly 18V? Or maybe the mm is reading a higher voltage??? Note what you are seeing.
To ensure safe operation and service of the meter, follow these instructions. Failure to observe these warnings can result in severe injury or death.
Page 5
.
Warning or Caution
Read Instructions
To ensure safe operation and service of this meter, follow all warnings and instructions detailed in this manual.
Risk of Electrical Shock
Improper use of this meter can lead to risk of electrical shock. Follow all warnings and instructions detailed in this manual
page 6
.
Pay close attention to pages 5 thru 14.
.
For all the testing you will be preforming the test leads are plugged into the, black lead into the Com (Common) jack and the red lead plug into the red "VΩ" jack. ("VΩ", Volt / Ohm Jack) Page 7
DO NOT attempt to measure continuity on a live circuit.
Page 13.
DO NOT attempt to measure resistance on a live circuit.
Page 14
NEVER plug the red test probe lead plug into the "10A" jack or "mA/μA" jack when measuring voltages. LIVE circuits. See page 12.
That would create a dead short across the LIVE circuit.
@obarrett- Thanks for clarifying on the connections. I'd take @jea48up on his offer to work with you directly. And a nice video on showing how everything is hooked up and what happened. A picture is worth a 1000 words.
One suggestion that I would make, and please don't take it the wrong way.... You need to cleanup your wiring. I'd also replace those plug-in 2to6 outlet adapters with at least a specifically designed AV power strip or even an old Monster Power HTS series unit from eBay if there is a budget constraint. Those 2to6 adapters always scare me because they typically not well made and can be overloaded and shorted way to easily.
Also, check the wiring/cabling itself. I see in the video that you have some stuff coiled up on the floor, etc. And just to rule it out, make sure you don't have something like a cut in a power cable that has shorted to the interconnects or to one of the chassis.
Hope you can figure out what happened and that nothing got permanently fried.
Subwoofer? You keep adding equipment... Does the 120Vac IEC inlet connector on the back of the sub have three prongs? Therein an equipment ground prong? My bet is yes. Correct?
*** Does the CDP use a grounded power cord? Therein the IEC inlet on the back of the CDP has a third prong for the equipment from the wall outlet?
I have been looking for an equipment ground that is grounding the chassis and or signal ground of the RR2160 amp through the outer plug shell ground of an RCA interconnect. If the subwoofer uses the wall outlet equipment grounding that may be the ground. I assume the sub was plugged into the 120vac wall outlet.. It doesn’t matter if the sub is powered on or off. If the cord is connected at both ends the sub chassis is grounded...
The equipment ground was/is the fault circuit path back to the source. That is if the subwoofer chassis is connected to the wall outlet safety equipment ground.
That’s a pretty good size bite out of the outer shell of the RCA plug on the interconnect cable. I didn’t see its’ mate on the RR2160 amp. It has to be there somewhere.
Sometime later today, Friday the 28th, I will work up a testing procedure. It would go a lot quicker if we could respond back and forth Friday night.
@jeffbijYes I’m sorry I misspoke. I was connecting to the RCA input of the amp, not the TT.
@jea48yes wired coax to router, then Ethernet from router to bluesound node. Ethernet is not shielded. Both cables pass close to the interconnects going to/from the preamp through the back of my cabinet. I made a video: https://youtu.be/dPq8B54utCw?si=o6S-uJqUXYGxfJiT.
yes, I meant analog input of my RR2160. Apologies.
spark from outer shell of RCA cable. In video I show exactly where as it left a crater in the metal casing. NOT the center pin of the interconnect.
i ordered the Klein tools MM720 you recommend. It should arrive tomorrow. Please tell me what tests I should start with and how to execute them. I’m not going to get a separate outlet tester if it can be achieved using the multimeter. Thanks for all your help.
it is actually the Southwire "10041N autoranging multimeter." I use it mostly for DC mA but occasionally I use it for checking continuity and less often for checking AC voltages.
It looks better. Also seems to have more user friendly features. Accuracy of AC voltage measurements??? It didn’t say it is a True RMS meter.
As for using the meter to check/set DC ma bias it is probably fine. Use the mA rotary switch setting. It should give a more accurate reading than using the 10 A setting.
Manual says 275 to 300 ma. My understanding that is too high.
My Son bought a V12 a few years ago at, I believe an Estate sale. He said he was having problems setting the bias. He brought it over for me to look at. I tested the KT88 power tubes in the amp. On the "Life Test" all tested good except two tested good marginal.
What didn't test good was the 4 small signal tubes. He bought 2 new 6922 tubes (input / driver tubes) and 2 SV83/EL84 tubes (Current source tubes).
While he was waiting for the new tubes he searched Cary chat forums on the Net. He found a good site that said the Cary manual bias settings were too high. I can't remember where we set the DC ma bias at. What ever it was he hasn't had any problems with the Amp. That is when he uses it...
No, @jea48, it is actually the Southwire "10041N autoranging multimeter." I use it mostly for DC mA but occasionally I use it for checking continuity and less often for checking AC voltages. It is not like I am a tech person, but I would like to think that the readings I am taking are close to being accurate.
As far as the bias on my amp, it is currently set at a few hairs (on both sides) under 260 mA. Without going back and checking, I am about sure the manual says 270 to 300; back at the end of '17 when Cary tech support would still take telephone calls, in some context the subject came up and the tech guy said to shoot for 40 to 50 mA a tube. (I think the context of that conversation was how to bias it if running less than six tubes per side.) @decooney told me that when he had his V-12 he liked it set way lower, but when I tried that I didn't think I liked it as well. Who knows, maybe it was psychological. on my end.
Just curious what are you setting the DC ma bias at?
@jea48, when my old Radio Shack meter failed the drop test and I needed a new one (like immediately to bias my amp) I went to Lowes (because they are super close) and I bought a South Wire. How do those stack up? I saw that they had Fluke meters, but for what I thought at the time was an ungodly amount of money. I could always upgrade to a Klein; I am pretty sure that now Lowes sells them as well.
RR2160 amp has built in DAC and has two coax inputs. One to CD player one to bluesound node.
bluesound node
Internet provider line into your home? Fiber, Coax cable, other?
Are you using WiFi or hard wired Ethernet cable to the bluesound node ? IF hard wired is the cable used a shielded ethernet cable? (Looking for a possible ground path)
.
(CDP digital out used as a transport)
Does the CDP use a grounded power cord?
yes you’re right the preamp was grounded to the tone arm.
IMO, that is the way it should be done. With multimeter you will verify the tone arm is not connected, grounded, to the TT EGC.
.
Incredibly, when I was unplugging the phono preamp, I actually got some current from simply touching the exterior of the box.
I thought you meant unplugging the preamp power supply from the wall outlet you were touching the metal "box" of the preamp with the other hand. Thus my questioning about the wall outlet cover plate. If metal it would be grounded. I was looking for a possible difference of potential, voltage, from the phono preamp metal "box", to ground that caused the electrical shock.
You clarified with this.
you asked what two metal objects I was connecting. I was connecting the interconnects from preamp OUTPUT to the analog INPUT of the TT.
analog INPUT of the TT. ??? You mean analog input of the RR2160 amp?
.
I had an idea which may be totally wrong but I noticed the blue light in the 110LP flickering the last couple months, and it’s connected to the circuit inside the preamp by a wire. Maybe something went wrong with that wire and it shorted to the exterior of the preamp box.
Don’t do any more experimenting using the phono preamp.
The normal operating input voltage of the phono preamp is 24Vdc. Power wise just a few watts. That normally will not cause sparks.
.
From original OP:
After getting things back into place, I listened to some music using coaxial input before reconnecting the interconnects of the phono stage. When I tried to, I actually got some electric current that burned my hand slightly. This came from the back of the amplifier. I made sure everything was unplugged and tried again - this time a spark and smoke from the interconnect making contact to the back of the amplifier.
That would imply a significant difference of potential, voltage, between the two points.
Just a guess you had your fingers of one hand holding the outer ground shell of the interconnect and touched the rear metal panel of the RR2160 amp with the same hand. (In and out points were the finger(s) of the hand.)
Sparks? From the outer ground shell of the interconnect plug to the rear panel or outer ground shell of the RCA jack on the RR2160 amp, OR center pin of interconnect cable to RR2160 amp? (Hopefully you were not successful in plugging the interconnect into the Line in RCA jack of the RR2160 amp.)
Where is the difference of potential, Voltage, power, coming from? That is where the multi meter comes in. I will instruct you where to use the multimeter.
If you do not also buy a plug-in circuit checker I will instruct you, using the multimeter, how to preform the same tests as the circuit tester.
Using the multimeter we will verify the RR2160 amp does not have an internal Hot 120V to metal chassis fault. We will try to run tests on all the associated equipment until faulted culprit is found.
.
I was going to just get a no contact voltmeter, but it seems maybe I should instead get a multimeter? Let me know what you would advise.
Multimeter...
As for checking the 120Vac wall outlet. A multimeter can preform the same tests as a plug-in circuit tester. Buy both if you want. If only buying one, buy a multimeter
as it turns out as others have pointed out, no ground pin was removed and the amp is by design ungrounded. I agree it’s dangerous. Could you elaborate on what an outlet tester would tell me?
A basic one would tell you if you if the wiring to the outlet was correct and reasonably functional. For instance, the ground wire may be missing or broken, in which case a ground pin on your gear would be useless.
Now that I think about it, get a more advanced one so you can see the N-E (neutral to earth) voltage. This will help you see also that the neutral wire is near ground (should be 2V or less).
you asked what two metal objects I was connecting. I was connecting the interconnects from preamp OUTPUT to the analog INPUT of the TT. those inputs are near the speaker wire plugs for the right speaker.
Do you mean that you connected the interconnect cables running FROM the turntable and plugged them into the INPUT connections on the Moon 110LP, and the ground cable from the turntable to the ground stud on the Moon 110LP as well? And then plugged interconnects from the OUTPUT connections on the Moon 110LP to one of the AUDIO IN connections on the Outlaw receiver, correct?
Thank you all for your responses. It’s a big help to me as I’m not an expert on electromagnetism.
@jeffbij although the amp is not grounded, it functions fine with no voltage/charge unless connected to the phono preamp. When connected to phono preamp it predictably becomes dangerous.
@erik_squiresas it turns out as others have pointed out, no ground pin was removed and the amp is by design ungrounded. I agree it’s dangerous. Could you elaborate on what an outlet tester would tell me?
@jea48 RR2160 amp has built in DAC and has two coax inputs. One to CD player one to bluesound node. Since this episode I’ve been listening to music off the node without problems. Thank you for pointing out the RR2160 doesn’t have a ground pin. At least one of us is paying attention, I guess. The preamp and amp are plugged into the same single duplex outlet; the TT is plugged into a different single duplex outlet but was OFF when this happened. Could you describe what information I could use a multimeter to obtain? I will get one if it will help diagnose.
yes you’re right the preamp was grounded to the tone arm.
yes the outlet cover is plastic and the plug in power supply for the photo preamp is plastic.
you asked what two metal objects I was connecting. I was connecting the interconnects from preamp OUTPUT to the analog INPUT of the TT. those inputs are near the speaker wire plugs for the right speaker. When I touched the interconnect from the preamp to the amp analog input the second time, there was a large SPARK and even some SMOKE. It created a small crater on the housing of the interconnect. Obviously extremely hazardous.
I had an idea which may be totally wrong but I noticed the blue light in the 110LP flickering the last couple months, and it’s connected to the circuit inside the preamp by a wire. Maybe something went wrong with that wire and it shorted to the exterior of the preamp box. It would be easy enough to check by disconnecting that wire, but first I need to get the appropriate equipment. I was going to just get a no contact voltmeter, but it seems maybe I should instead get a multimeter? Let me know what you would advise.
The OP should first locate the problem. Was it the phono preamp power supply that caused the problem?
Or was it x or y or z that caused the problem that damaged the phono preamp?
.
FYI, in older homes with old two wire branch circuit wiring, a plug-in circuit tester works good for finding reversed AC polarity. They will tell you if there is an OPEN GROUND. What they don’t tell you if the tester says OK is the EGC (Equipment Grounding Conductor) really an EGC that runs back to the electrical panel or is it a Boot Leg EGC created by installing a jumper from the neutral terminal on a duplex receptacle to the EGC terminal screw on the outlet. It will also not tell you if the neutral conductor and EGC conductor are reversed on the outlet.
Safety advice: do not turn on the questionable electronics until repaired, and get a socket tester for your house. They’re not expensive and are worth getting.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.
